1. Field of the Invention
This invention relates to monochromators.
2. Prior Art
Monochromators which can produce a monochromatic beam with narrow spectral wavebands are known. Such beams are very useful in the testing and calibrating of x-ray telescopes and microscopes, in research in biological and biomedical disciplines, in research in properties of materials and processing etc.
Previous monochromators have used metal foil filters, gratings, or crystals. Metal foil monochromators have the advantage of a high throughput but do not have the narrow bandwidth needed for some applications. Much higher spectral resolution is possible with the use of crystal or grating monochromators but these have other disadvantages.
Natural crystal monochromators are suitable for hard x-ray use and even some of the shorter wavelengths in the soft x-ray wavelengths but the crystal lattice structure in naturally occurring crystals is too small to permit observations in the longer wavelength soft x-ray/EUV regimes. Grating monochromators are capable of covering the soft x-ray/EUV portions of the electromagnetic spectrum, which is the concern of the present invention, but they have a very low throughput.
In addition, grating monochromators are difficult to fabricate, align and maintain in optical alignment. Also, grating monochromators are typically large and expensive.